Being able to provide outstanding performances under out-of-plane loading, sandwich structures of... more Being able to provide outstanding performances under out-of-plane loading, sandwich structures offer great flexibility for the design of lightweight structural systems. However, they can be affected by macroscopic and microscopic damages, which may trigger catastrophic failure modes. As a consequence, a detailed understanding of the propagation of macro-cracks in the core as well as of delamination phenomena at face-to-core interfaces are aspects of great computational interest. Moreover, linking sophisticated numerical models with the measurement of the mechanical properties of materials is fundamental in view of actual engineering applications. The elastic and fracture characterization of the core is particularly relevant because its cracking strongly reduces the capacity of the sandwich structures to carry out loads. To this end, PVC foams typically used as inner core in structural application are investigated over a range of foam densities. Firstly, the elastic properties of foams under compressive uni-axial loading are measured using the full-field methodology. Subsequently, Asymmetric Semi-Circular Bend (ASCB) specimens are tested varying the position of supports to generate all range of mixed fracture modes. Finally, some of the mostly recognized fracture criterions have been considered, and their capability to compute the crack propagation angles in PVC foams have been evaluated. The parameters experimentally determined have been used to test the accuracy of the response provided by a numerical model developed by the authors.
A parametric analysis of the nonlinear static behaviour of selfanchored long-span bridges is here... more A parametric analysis of the nonlinear static behaviour of selfanchored long-span bridges is here carried out by using a 3D nonlinear finite element model of the bridge. Both cable-stayed bridges with a fan-shaped arrangement of stays and combined cable-stayed-suspension bridges are considered in the numerical investigations. The importance of an accurate description of geometrically nonlinear effects, arising from the cables nonlinear behavior in coupling with the instability effect of axial compression in girder and pylons, is pointed out by means of comparisons with results obtained by using different cable models. Numerical simulations are devoted to analyze the influence of the main physical characteristics of the bridge, on the maximum load-carrying capacity and related collapse mechanisms. A nonlinear procedure for finding the initial geometry of the bridge and prestress distribution under dead load is incorporated in the model. The strong role of nonlinear cables response, i...
A numerical study is proposed to investigate the structural behavior of network arch bridges subj... more A numerical study is proposed to investigate the structural behavior of network arch bridges subjected to the cable loss accidental event. The main aim of the paper is to analyze the effects produced by potential cable loss scenarios on the main stress and kinematic design variables of the structure. To this end, a parametric study in terms of the main structural and geometric parameters is developed with the purpose to identify the key factors that contribute to reduce hazards produced by the cable loss event. The structural analyses are performed by using a refined FE nonlinear geometric formulation, in which the influence of large displacements and local vibrations of cable elements are taken into account. The loss of the cable is reproduced by means of a proper damage law, developed in the framework of Continuum Damage Mechanics theory. Cable loss analyses are performed by means of both nonlinear dynamic analyses and simplified methodologies proposed by existing codes on cable s...
An analysis on the effects produced by failure mechanisms in the cable system is proposed to inve... more An analysis on the effects produced by failure mechanisms in the cable system is proposed to investigate the behavior of cable-stayed bridges. In particular, the present paper aims to verify the influence on the bridge behavior of accidental breakages produced in the cable system elements also in light of existing design guidelines available from the literature. In the present paper, the numerical model is based on a refined description of the bridge, which involves bridge constituents and external loads. In particular, a geometric nonlinear formulation in which the effects of local vibrations in the stays and large displacements in girder and pylons are taken into account. Moreover, damage effects are simulated by using an accurate description of the release effects produced by the cable-breakage processes. The results denote that several parameters associated with cable-breakage processes, such as the breakage duration, time-transient curve and external load description, are found...
A general model to predict dynamic behavior of interfacial cracks in laminated structures is prop... more A general model to predict dynamic behavior of interfacial cracks in laminated structures is proposed. The model is developed on a combined approach based on Fracture Mechanics and moving mesh methodology. The former is utilized to predict the crack growth, whereas the latter defines the way to take in account for the geometry changes on the basis of the invoked fracture parameters. Consistently to the Fracture Mechanics, the crack propagation depends from the energy release rate and its mode components, which are calculated by means of the decomposition methodology of the J-integral expression. The geometry variation, produced by the crack advance, is taken into account by means of a moving mesh strategy based on the Arbitrary Lagrangian-Eulerian (ALE) formulation. The coupling characters of the governing equations of the proposed model arising from the Fracture Mechanics and the moving mesh methodology are discussed. Comparisons with experimental results are reported to validate t...
International Journal of Solids and Structures, 2006
This work describes an improved technique for the analysis of interlaminar crack growth in lamina... more This work describes an improved technique for the analysis of interlaminar crack growth in laminated circular beams subjected to mixed-mode loading conditions. By adopting a multi-layer curved beam model and curved interface elements leads to model the structure as a succession of first-order shear deformable beams joined by adhesive interfaces. The interface containing the crack is simulated by means of a cracking linear interfacial constitutive law which provides normal and shear interlaminar stresses. At the perfectly bonded interfaces the connection between beam elements is imposed by the Lagrange multiplier method. The total energy release rate and its individual mode components are obtained when the stiffnesses, considered as penalty parameters, tend to infinity thus reproducing the results of the linear elastic fracture mechanics theory. Results are obtained by adopting an accurate numerical integration procedure able to deal with stress singularities at the crack tip. Comparisons with results available from literature obtained by using the elasticity theory and solid finite elements show that the model is able to capture accurately both the total and the individual mode components of energy release rate. Numerical examples demonstrate the capability of the proposed method to provide a complete description of the problem of mixed-mode crack growth in curved interfaces, which takes into account the influence of curvature and of transverse shear deformability.
A dynamic model to predict crack growth phenomena in z-pinned reinforced composite structures is ... more A dynamic model to predict crack growth phenomena in z-pinned reinforced composite structures is proposed. The formulation is based on a novel technique, which is able to couple Fracture Mechanics concepts with a strategy based on a moving mesh methodology. The former is utilized to predict the crack growth, whereas the latter defines the way to take into account the geometry changes on the basis of the invoked fracture parameters. The presence of the z-pins is simulated by means of a largescale bridging approach, introducing along the delaminated interfaces normal and tangential traction forces depending on the dynamic characteristics of the pull-out mechanism. In order to evaluate the fracture parameters, which govern the crack evolution, the J-integral decomposition procedure is utilized, providing new expressions in the framework of a large-scale bridging crack growth. A numerical modeling based on the finite element procedure is implemented and comparisons with experimental results are reported to validate the proposed formulation. Moreover, a parametric study is developed to investigate the influence of z-pins on the crack growth mechanisms.
International Journal of Solids and Structures, 2003
An accurate laminate model developed by using multilayer shear deformable plate modeling and inte... more An accurate laminate model developed by using multilayer shear deformable plate modeling and interface elements, based on fracture mechanics and contact mechanics, is proposed to analyze mixed mode delamination in composite laminates. Perfect adhesion along the ...
International Journal of Solids and Structures, 2010
An analysis of the effects of microscopic instabilities on the homogenized response of heterogene... more An analysis of the effects of microscopic instabilities on the homogenized response of heterogeneous solids with periodic microstructure and incrementally linear constitutive law is here carried out. In order to investigate the possibility to obtain a conservative prediction of microscopic primary instability in terms of homogenized properties, novel macroscopic constitutive stability measures are introduced, corresponding to the positive definiteness of the homogenized moduli tensors relative to a class of conjugate stress-strain pairs. Numerical simulations, addressed to hyperelastic microstructural models representing cellular solids and reinforced composites, are worked out through the implementation of an innovative one-way coupled finite element formulation able to determine sequentially the principal equilibrium solution, the incremental equilibrium solutions providing homogenized moduli and the stability eigenvalue problem solution, for a given monotonic macrostrain path. Both uniaxial and equibiaxial loading conditions are considered. The exact microscopic stability region in the macrostrain space, obtained by taking into account microstructural details, is compared with the macroscopic stability regions determined by means of the introduced macroscopic constitutive measures. These results highlight how the conservativeness of the adopted macroscopic constitutive stability measure with respect to microscopic primary instability, strictly depends on the type of loading condition (tensile or compressive) and the kind of microstructure.
Abstract A numerical investigation on the nonlinear static behavior of self-anchored long span ca... more Abstract A numerical investigation on the nonlinear static behavior of self-anchored long span cable-stayed bridges with a fan-shaped arrangement of stays is carried out by adopting a spatial finite element model of the bridge. An equivalent continuous model of the bridge is also developed in order to point out the main parameters governing the non-linear behavior of the bridge to be used in the more general 3D discrete bridge analysis and to provide a validation of the discrete model. The importance of an accurate description of geometrically nonlinear effects arising from the stays nonlinear response in coupling with the instability effect of axial compression in girder and pylons, is evaluated by means of original comparisons with results obtained by using simplified assumptions. Novel parametric studies are performed for investigating the influence of the main geometrical and material design parameters derived from the continuous model formulation on the maximum load-carrying capacity of the bridge and related collapse mechanisms. Different loading conditions, also including live load eccentricities, and pylon shapes are also considered and a nonlinear procedure for finding the initial geometry and prestress distribution under dead load is incorporated in the analysis. The results point out the strong role of nonlinear stays response, especially when the assumed loading condition produces cable unloading, in coupling with the notable influence of the relative girder stiffness on the stability bridge behavior. On the contrary, in general pylon shape and stiffness, live load eccentricity and torsional stiffness are less important factors in non-linear analysis.
In this work a technique for analyzing mixed mode delamination problems in laminated composite pl... more In this work a technique for analyzing mixed mode delamination problems in laminated composite plates under general loading conditions is developed. The technique adopts the first-order shear deformable laminated plate theory and the interface methodology, which in turn is based on fracture and contact mechanics. In the thickness direction, an assembly of laminated plate and interfaces models the laminated structure. Delamination may occur along these interfaces, which otherwise perfectly connect the plate models by considering the limit case of interface stiffness coefficients approaching infinity. Lagrange and penalty methods are adopted in order to simulate adhesion and contact effects. Analytical expressions for total energy release rate and its mode components along the delamination front are given in terms of interface variables and of plate stress resultant discontinuities. By means of these expressions the influence of transverse shear on interface fracture analysis is investigated and comparisons with other plate-based delamination models adopted in the literature are established. Numerical results for the energy release rate distributions are given for typical mixed mode delamination problems by implementing the method in a 2D finite element analysis, which utilizes shear deformable plate elements and interface elements. Comparisons with full 3D finite element models show the accuracy and the computational efficiency of the proposed procedure. Some applications are proposed to point out the influence of delamination faces interaction on delamination analysis and the convergence of the mode partition procedure as the delamination front element size decreases, also when oscillatory singularities exist. On the basis of the latter result it transpires that the proposed interface model may represent the physical situation of a very thin adhesive layer.
The macroscopic response of elastic composite materials with periodic defected microstructures un... more The macroscopic response of elastic composite materials with periodic defected microstructures under large deformations is analyzed. The effects of microscopic instability and bifurcation are studied by using an updated Lagrangian formulation and frictionless self-contact between crack faces is accounted. Two special classes of homogenization problems are examined: effective contact and self-adjoint data. Numerical applications are developed by means of an FE approach with reference to a cellular material with diagonal microcracks and to a laminated microstructure with interface debonding. The strong role of crack self-contact nonlinearities and the influence of microscopic defects on the homogenized composite properties are pointed out.
ABSTRACT A dynamic modeling technique able to reproduce interfacial debonding phenomena in FRP re... more ABSTRACT A dynamic modeling technique able to reproduce interfacial debonding phenomena in FRP reinforced concrete beams is proposed to investigate the unstable behavior of concrete beams produced by interlaminar debonding mechanisms. The structural formulation adopts plane stress modeling and beam theory to predict the behavior of the RC beam and the FRP external reinforcement, respectively. The proposed methodology is consistent with a numerical methodology, which couples the Arbitrary Lagrangian–Eulerian (ALE) formulation with the Fracture Mechanics approach. The moving mesh strategy is used to reproduce the crack tip growth at the interfacial scale level by means of a geometry variation of the computational mesh points. Moreover, fracture variables, evaluated by means of the J-integral decomposition technique, define the crack growth motion during the debonding phenomena on the basis of an explicit crack tip speed criterion. Comparisons between static and dynamic behaviors are proposed to quantify, numerically, the dynamic amplification effects on the debonding variables produced by external and inertial loads. Moreover, a parametric study in terms of the structural characteristics of the beam constituents is developed to investigate the effects produced by the dynamic nature of the debonding phenomena on the crack evolution.
An analysis of doubly curved shells, based on Sanders' theory, is developed to study shear-deform... more An analysis of doubly curved shells, based on Sanders' theory, is developed to study shear-deformable laminated composite shells made of bimodular materials. The theory takes into account geometric and material nonlinearities. Material nonlinearities are modeled by the fibergoverned Bert scheme. Thin and thick doubly curved shells subjected to sinusoidal or uniformly distributed loading are analyzed. Closed-form and numerical FEM solutions are compared for simply supported cross-ply doubly curved shells subjected to sinusoidally distributed loading. The numerical examples presented demonstrate the effectiveness of the FEM procedure adopted and show the influence of boundary conditions, lamination scheme, and geometric and material nonlinearities.
Being able to provide outstanding performances under out-of-plane loading, sandwich structures of... more Being able to provide outstanding performances under out-of-plane loading, sandwich structures offer great flexibility for the design of lightweight structural systems. However, they can be affected by macroscopic and microscopic damages, which may trigger catastrophic failure modes. As a consequence, a detailed understanding of the propagation of macro-cracks in the core as well as of delamination phenomena at face-to-core interfaces are aspects of great computational interest. Moreover, linking sophisticated numerical models with the measurement of the mechanical properties of materials is fundamental in view of actual engineering applications. The elastic and fracture characterization of the core is particularly relevant because its cracking strongly reduces the capacity of the sandwich structures to carry out loads. To this end, PVC foams typically used as inner core in structural application are investigated over a range of foam densities. Firstly, the elastic properties of foams under compressive uni-axial loading are measured using the full-field methodology. Subsequently, Asymmetric Semi-Circular Bend (ASCB) specimens are tested varying the position of supports to generate all range of mixed fracture modes. Finally, some of the mostly recognized fracture criterions have been considered, and their capability to compute the crack propagation angles in PVC foams have been evaluated. The parameters experimentally determined have been used to test the accuracy of the response provided by a numerical model developed by the authors.
A parametric analysis of the nonlinear static behaviour of selfanchored long-span bridges is here... more A parametric analysis of the nonlinear static behaviour of selfanchored long-span bridges is here carried out by using a 3D nonlinear finite element model of the bridge. Both cable-stayed bridges with a fan-shaped arrangement of stays and combined cable-stayed-suspension bridges are considered in the numerical investigations. The importance of an accurate description of geometrically nonlinear effects, arising from the cables nonlinear behavior in coupling with the instability effect of axial compression in girder and pylons, is pointed out by means of comparisons with results obtained by using different cable models. Numerical simulations are devoted to analyze the influence of the main physical characteristics of the bridge, on the maximum load-carrying capacity and related collapse mechanisms. A nonlinear procedure for finding the initial geometry of the bridge and prestress distribution under dead load is incorporated in the model. The strong role of nonlinear cables response, i...
A numerical study is proposed to investigate the structural behavior of network arch bridges subj... more A numerical study is proposed to investigate the structural behavior of network arch bridges subjected to the cable loss accidental event. The main aim of the paper is to analyze the effects produced by potential cable loss scenarios on the main stress and kinematic design variables of the structure. To this end, a parametric study in terms of the main structural and geometric parameters is developed with the purpose to identify the key factors that contribute to reduce hazards produced by the cable loss event. The structural analyses are performed by using a refined FE nonlinear geometric formulation, in which the influence of large displacements and local vibrations of cable elements are taken into account. The loss of the cable is reproduced by means of a proper damage law, developed in the framework of Continuum Damage Mechanics theory. Cable loss analyses are performed by means of both nonlinear dynamic analyses and simplified methodologies proposed by existing codes on cable s...
An analysis on the effects produced by failure mechanisms in the cable system is proposed to inve... more An analysis on the effects produced by failure mechanisms in the cable system is proposed to investigate the behavior of cable-stayed bridges. In particular, the present paper aims to verify the influence on the bridge behavior of accidental breakages produced in the cable system elements also in light of existing design guidelines available from the literature. In the present paper, the numerical model is based on a refined description of the bridge, which involves bridge constituents and external loads. In particular, a geometric nonlinear formulation in which the effects of local vibrations in the stays and large displacements in girder and pylons are taken into account. Moreover, damage effects are simulated by using an accurate description of the release effects produced by the cable-breakage processes. The results denote that several parameters associated with cable-breakage processes, such as the breakage duration, time-transient curve and external load description, are found...
A general model to predict dynamic behavior of interfacial cracks in laminated structures is prop... more A general model to predict dynamic behavior of interfacial cracks in laminated structures is proposed. The model is developed on a combined approach based on Fracture Mechanics and moving mesh methodology. The former is utilized to predict the crack growth, whereas the latter defines the way to take in account for the geometry changes on the basis of the invoked fracture parameters. Consistently to the Fracture Mechanics, the crack propagation depends from the energy release rate and its mode components, which are calculated by means of the decomposition methodology of the J-integral expression. The geometry variation, produced by the crack advance, is taken into account by means of a moving mesh strategy based on the Arbitrary Lagrangian-Eulerian (ALE) formulation. The coupling characters of the governing equations of the proposed model arising from the Fracture Mechanics and the moving mesh methodology are discussed. Comparisons with experimental results are reported to validate t...
International Journal of Solids and Structures, 2006
This work describes an improved technique for the analysis of interlaminar crack growth in lamina... more This work describes an improved technique for the analysis of interlaminar crack growth in laminated circular beams subjected to mixed-mode loading conditions. By adopting a multi-layer curved beam model and curved interface elements leads to model the structure as a succession of first-order shear deformable beams joined by adhesive interfaces. The interface containing the crack is simulated by means of a cracking linear interfacial constitutive law which provides normal and shear interlaminar stresses. At the perfectly bonded interfaces the connection between beam elements is imposed by the Lagrange multiplier method. The total energy release rate and its individual mode components are obtained when the stiffnesses, considered as penalty parameters, tend to infinity thus reproducing the results of the linear elastic fracture mechanics theory. Results are obtained by adopting an accurate numerical integration procedure able to deal with stress singularities at the crack tip. Comparisons with results available from literature obtained by using the elasticity theory and solid finite elements show that the model is able to capture accurately both the total and the individual mode components of energy release rate. Numerical examples demonstrate the capability of the proposed method to provide a complete description of the problem of mixed-mode crack growth in curved interfaces, which takes into account the influence of curvature and of transverse shear deformability.
A dynamic model to predict crack growth phenomena in z-pinned reinforced composite structures is ... more A dynamic model to predict crack growth phenomena in z-pinned reinforced composite structures is proposed. The formulation is based on a novel technique, which is able to couple Fracture Mechanics concepts with a strategy based on a moving mesh methodology. The former is utilized to predict the crack growth, whereas the latter defines the way to take into account the geometry changes on the basis of the invoked fracture parameters. The presence of the z-pins is simulated by means of a largescale bridging approach, introducing along the delaminated interfaces normal and tangential traction forces depending on the dynamic characteristics of the pull-out mechanism. In order to evaluate the fracture parameters, which govern the crack evolution, the J-integral decomposition procedure is utilized, providing new expressions in the framework of a large-scale bridging crack growth. A numerical modeling based on the finite element procedure is implemented and comparisons with experimental results are reported to validate the proposed formulation. Moreover, a parametric study is developed to investigate the influence of z-pins on the crack growth mechanisms.
International Journal of Solids and Structures, 2003
An accurate laminate model developed by using multilayer shear deformable plate modeling and inte... more An accurate laminate model developed by using multilayer shear deformable plate modeling and interface elements, based on fracture mechanics and contact mechanics, is proposed to analyze mixed mode delamination in composite laminates. Perfect adhesion along the ...
International Journal of Solids and Structures, 2010
An analysis of the effects of microscopic instabilities on the homogenized response of heterogene... more An analysis of the effects of microscopic instabilities on the homogenized response of heterogeneous solids with periodic microstructure and incrementally linear constitutive law is here carried out. In order to investigate the possibility to obtain a conservative prediction of microscopic primary instability in terms of homogenized properties, novel macroscopic constitutive stability measures are introduced, corresponding to the positive definiteness of the homogenized moduli tensors relative to a class of conjugate stress-strain pairs. Numerical simulations, addressed to hyperelastic microstructural models representing cellular solids and reinforced composites, are worked out through the implementation of an innovative one-way coupled finite element formulation able to determine sequentially the principal equilibrium solution, the incremental equilibrium solutions providing homogenized moduli and the stability eigenvalue problem solution, for a given monotonic macrostrain path. Both uniaxial and equibiaxial loading conditions are considered. The exact microscopic stability region in the macrostrain space, obtained by taking into account microstructural details, is compared with the macroscopic stability regions determined by means of the introduced macroscopic constitutive measures. These results highlight how the conservativeness of the adopted macroscopic constitutive stability measure with respect to microscopic primary instability, strictly depends on the type of loading condition (tensile or compressive) and the kind of microstructure.
Abstract A numerical investigation on the nonlinear static behavior of self-anchored long span ca... more Abstract A numerical investigation on the nonlinear static behavior of self-anchored long span cable-stayed bridges with a fan-shaped arrangement of stays is carried out by adopting a spatial finite element model of the bridge. An equivalent continuous model of the bridge is also developed in order to point out the main parameters governing the non-linear behavior of the bridge to be used in the more general 3D discrete bridge analysis and to provide a validation of the discrete model. The importance of an accurate description of geometrically nonlinear effects arising from the stays nonlinear response in coupling with the instability effect of axial compression in girder and pylons, is evaluated by means of original comparisons with results obtained by using simplified assumptions. Novel parametric studies are performed for investigating the influence of the main geometrical and material design parameters derived from the continuous model formulation on the maximum load-carrying capacity of the bridge and related collapse mechanisms. Different loading conditions, also including live load eccentricities, and pylon shapes are also considered and a nonlinear procedure for finding the initial geometry and prestress distribution under dead load is incorporated in the analysis. The results point out the strong role of nonlinear stays response, especially when the assumed loading condition produces cable unloading, in coupling with the notable influence of the relative girder stiffness on the stability bridge behavior. On the contrary, in general pylon shape and stiffness, live load eccentricity and torsional stiffness are less important factors in non-linear analysis.
In this work a technique for analyzing mixed mode delamination problems in laminated composite pl... more In this work a technique for analyzing mixed mode delamination problems in laminated composite plates under general loading conditions is developed. The technique adopts the first-order shear deformable laminated plate theory and the interface methodology, which in turn is based on fracture and contact mechanics. In the thickness direction, an assembly of laminated plate and interfaces models the laminated structure. Delamination may occur along these interfaces, which otherwise perfectly connect the plate models by considering the limit case of interface stiffness coefficients approaching infinity. Lagrange and penalty methods are adopted in order to simulate adhesion and contact effects. Analytical expressions for total energy release rate and its mode components along the delamination front are given in terms of interface variables and of plate stress resultant discontinuities. By means of these expressions the influence of transverse shear on interface fracture analysis is investigated and comparisons with other plate-based delamination models adopted in the literature are established. Numerical results for the energy release rate distributions are given for typical mixed mode delamination problems by implementing the method in a 2D finite element analysis, which utilizes shear deformable plate elements and interface elements. Comparisons with full 3D finite element models show the accuracy and the computational efficiency of the proposed procedure. Some applications are proposed to point out the influence of delamination faces interaction on delamination analysis and the convergence of the mode partition procedure as the delamination front element size decreases, also when oscillatory singularities exist. On the basis of the latter result it transpires that the proposed interface model may represent the physical situation of a very thin adhesive layer.
The macroscopic response of elastic composite materials with periodic defected microstructures un... more The macroscopic response of elastic composite materials with periodic defected microstructures under large deformations is analyzed. The effects of microscopic instability and bifurcation are studied by using an updated Lagrangian formulation and frictionless self-contact between crack faces is accounted. Two special classes of homogenization problems are examined: effective contact and self-adjoint data. Numerical applications are developed by means of an FE approach with reference to a cellular material with diagonal microcracks and to a laminated microstructure with interface debonding. The strong role of crack self-contact nonlinearities and the influence of microscopic defects on the homogenized composite properties are pointed out.
ABSTRACT A dynamic modeling technique able to reproduce interfacial debonding phenomena in FRP re... more ABSTRACT A dynamic modeling technique able to reproduce interfacial debonding phenomena in FRP reinforced concrete beams is proposed to investigate the unstable behavior of concrete beams produced by interlaminar debonding mechanisms. The structural formulation adopts plane stress modeling and beam theory to predict the behavior of the RC beam and the FRP external reinforcement, respectively. The proposed methodology is consistent with a numerical methodology, which couples the Arbitrary Lagrangian–Eulerian (ALE) formulation with the Fracture Mechanics approach. The moving mesh strategy is used to reproduce the crack tip growth at the interfacial scale level by means of a geometry variation of the computational mesh points. Moreover, fracture variables, evaluated by means of the J-integral decomposition technique, define the crack growth motion during the debonding phenomena on the basis of an explicit crack tip speed criterion. Comparisons between static and dynamic behaviors are proposed to quantify, numerically, the dynamic amplification effects on the debonding variables produced by external and inertial loads. Moreover, a parametric study in terms of the structural characteristics of the beam constituents is developed to investigate the effects produced by the dynamic nature of the debonding phenomena on the crack evolution.
An analysis of doubly curved shells, based on Sanders' theory, is developed to study shear-deform... more An analysis of doubly curved shells, based on Sanders' theory, is developed to study shear-deformable laminated composite shells made of bimodular materials. The theory takes into account geometric and material nonlinearities. Material nonlinearities are modeled by the fibergoverned Bert scheme. Thin and thick doubly curved shells subjected to sinusoidal or uniformly distributed loading are analyzed. Closed-form and numerical FEM solutions are compared for simply supported cross-ply doubly curved shells subjected to sinusoidally distributed loading. The numerical examples presented demonstrate the effectiveness of the FEM procedure adopted and show the influence of boundary conditions, lamination scheme, and geometric and material nonlinearities.
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Papers by Domenico Bruno